The present invention relates to a self-tightening shoe; that is a shoe which can close itself to a desired value of tightness around a foot upon the press of a button.
The term “shoe” is used generically herein to encompass any types of footwear including leather shoes, sneakers, slippers, boots and the like.
The most common form of closure mechanism for a shoe is a lace, criss-crossing between the medial and lateral portions of the shoe upper, that is pulled tight around the instep of the foot and tied in a knot by the wearer. While simple and practical in functionality, such shoelaces need to be tied by hand and often retied as they naturally loosen around the wearer's foot. Young children who have not yet learned to tie a knot require assistance from an attentive parent or caregiver. Elderly people suffering from arthritis may find it painful or difficult. to pull shoelaces tight and tie knots in order to secure the shoes on their feet.
In order to alleviate this problem of tying shoelaces, shoes for children and adults have been provided with Velcro straps in lieu of the shoelaces. Such straps, extending from one side of the shoe are readily fastened to a complimentary Velcro patch secured to the other side of the shoe. However, such Velcro closures can frequently become detached, particularly in the case of athletic shoes and hiking boots, when excessive stress is applied. Moreover, Velcro closures can become worn, losing their capacity to close securely. Furthermore, many wearers find Velcro straps on footwear to he insufficiently tight and/or aesthetically unacceptable.
Numerous inventions, patented and unpatented, have been directed to solving the problems associated with shoelaces and other closure devices for shoes. For example, the U.S. Pat. No. 7,661,205 to Johnson discloses an “automated tightening shoe” of the type having criss-crossed laces which enables a user to pull a single tightening member at the heel of the shoe to tighten the laces. Once tightened to a desired value, the laces are secured by a mechanical latching mechanism until the mechanism is released.
The U.S. Pat. No. 6,598,322 to Jacques et al. teaches a shoe having laces connected to elongated shape memory alloy elements. When energised by an electric circuit, the shape memory elements shorten themselves and tighten the shoelaces. A push button, switch mounted on the shoe allows the user to manually activate an electronic switch to pass current through the shape memory elements causing them to heat sufficiently to reach their transformation temperature to tighten the laces.